Relative expression of KLK5 to LEKTI is associated with aggressiveness of oral squamous cell carcinoma

Bioinformatics analysis of human kallikrein 5 (KLK5) expression in metaplastic triple-negative breast cancer

Background

Metaplastic breast carcinoma (MBC) is a rare breast cancer subtype; most cases are triple-negative breast cancers (TNBCs) and are poorly responsive to conventional systemic therapy. Few potential diagnostic and prognostic markers for distinguishing between metaplastic TNBC and nonmetaplastic TNBC have been discovered. We performed bioinformatic analysis to explore the underlying mechanism by which metaplastic TNBC differs from nonmetaplastic TNBC and provides potential pathogenic genes of metaplastic TNBC.

Methods

Differentially expressed genes (DEGs) in metaplastic tumors and nonmetaplastic tumors from TNBC patients were screened using GSE165407. The GSE76275 data set and The Cancer Genome Atlas (TCGA) database were used to screen DEGs in TNBC and non-TNBC. Metascape and DAVID were used for the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis and Gene Ontology (GO) analysis of DEGs. Online databases, including UALCAN, GEPIA, HPA, Breast Cancer Gene-Expression Miner, and quantitative PCR and western blot, were used to examine KLK5 messenger RNA and protein expression in breast cancer. Analysis of KLK5‑associated genes was performed with TCGA data, and the LinkedOmics database was used to detect the genes co-expressed with KLK5. STRING (Search Tool for the Retrieval of Interacting Genes) and Cytoscape were used to screen for hub genes. Kaplan‑Meier plotter was used for survival analysis.

Results

KLK5 was identified among the DEGs in nonmetaplastic TNBC and metaplastic TNBC. The KLK5 gene was overexpressed in nonmetaplastic TNBC but downregulated in metaplastic TNBC. KEGG and GO analyses revealed that epithelial-to-mesenchymal transition was a pathogenic mechanism in metaplastic TNBC and an important pathway by which KLK5 and its associated genes DSG1 and DSG3 influence metaplastic TNBC progression. Prognosis analysis showed that only low expression of KLK5 in metaplastic TNBC had clinical significance.

Conclusion

Our research indicated that KLK5 may be a pivotal molecule with a key role in the mechanism of tumorigenesis in metaplastic TNBC.

Metformin inhibits melanoma cell metastasis by suppressing the miR-5100/SPINK5/STAT3 axis

Melanoma is the most lethal skin cancer characterized by its high metastatic potential. It is urgent to find novel therapy strategies to overcome this feature. Metformin has been confirmed to suppress invasion and migration of various types of cancer. However, additional mechanisms underlying the antimetastatic effect of metformin on melanoma require further investigation. Here, we performed microarray analysis and uncovered an altered mRNA and miRNA expression profile between melanoma and nevus. Luciferase reporter assay confirmed that miR-5100 targets SPINK5 to activate STAT3 phosphorylation. Migration and wound healing assays showed that the miR-5100/SPINK5/STAT3 axis promotes melanoma cell metastasis; the mechanism was proven by initiation of epithelial–mesenchymal transition. Co-immunoprecipitation (Co-IP) further confirmed an indirect interaction between SPINK5 and STAT3. Furthermore, metformin dramatically inhibited miR-5100/SPINK5/STAT3 pathway, and decreased B16-F10 cell metastasis to lung in C57 mouse module. Intriguingly, pretreatment of metformin before melanoma cell injection improved this effect further. These findings exposed the underlying mechanisms of action of metformin and update the use of this drug to prevent metastasis in melanoma.

SPINKs in Tumors: Potential Therapeutic Targets

The serine protease inhibitor Kazal type (SPINK) family includes SPINK1-14 and is the largest branch in the serine protease inhibitor family. SPINKs play an important role in pancreatic physiology and disease, sperm maturation and capacitation, Nager syndrome, inflammation and the skin barrier. Evidence shows that the unregulated expression of SPINK1, 2, 4, 5, 6, 7, and 13 is closely related to human tumors. Different SPINKs exhibit various regulatory modes in different tumors and can be used as tumor prognostic markers. This article reviews the role of SPINK1, 2, 4, 5, 6, 7, and 13 in different human cancer processes and helps to identify new cancer treatment targets.

SPINK5 is a Prognostic Biomarker Associated With the Progression and Prognosis of Laryngeal Squamous Cell Carcinoma Identified by Weighted Gene Co-Expression Network Analysis

Laryngeal squamous cell carcinoma (LSCC) is one of the most common types of head and neck squamous cell carcinomas (HNSCC) and is the second most prevalent malignancy occurring in the head and neck or respiratory tract, with a high incidence and mortality rate. Survival is limited for patients with LSCC. To identify more biomarkers associated with the prognosis of patients with LSCC, using bioinformatics analysis, this study used The Cancer Genome Atlas (TCGA) LSCC dataset and gene expression profiles of GSE59102 from the Gene Expression Omnibus (GEO). Eighty-one differentially co-expressed genes were identified by weighted gene co-expression network analysis (WGCNA). Next, 10 hub genes (PPL, KRT78, CRNN, PTK7, SCEL, AGRN, SPINK5, AIF1L, EMP1, and PPP1R3C) were screened from a protein-protein interaction (PPI) network. Based on survival analysis, SPINK5 was significantly correlated with survival time in LSCC patients. After verification in the TCGA and HPA databases, SPINK5 was selected as a prognostic biomarker. Finally, the GSEA results showed that downregulation of SPINK5 gene expression may promote tumorigenesis and the development of cancers by the “BASAL CELL CARCINOMA” pathway, and it has been implicated in disrupting DNA damage and repair pathways. Collectively, SPINK5 may serve as a potential prognostic biomarker in LSCC.

CEBPB knockdown sensitizes nasopharyngeal carcinoma cells to cisplatin by promoting the expression of serine protease inhibitor Kazal-type 5

Serine protease inhibitor Kazal-type 5 (SPINK5) has been indicated to act as a prognostic predictor for patients with head and neck squamous cell carcinoma. However, its specific role in nasopharyngeal carcinoma (NPC), a malignancy that has a high propensity for chemoresistance, remains largely obscure. We, thus, sought to investigate the importance of SPINK5 expression in regulating chemoresistance in NPC. Differentially expressed genes in NPC were screened using the cancer genome atlas-head and neck squamous cell carcinoma database and microarray analysis. SPINK5 was downregulated in NPC tissues and cells. After SPINK5 upregulation, the cells treated with cisplatin showed reduced cell survival and the ability to migrate, invade and metastasize. Mechanistically, the transcription factors regulating SPINK5 were queried through the JASPAR website, followed by dual-luciferase and Chromatin immunoprecipitation assay validation. CCAAT enhancer-binding protein (CEBP) beta (CEBPB) bound to the SPINK5 promoter region in NPC cells. The silencing of CEBPB enhanced the expression of SPINK5. CEBPB overexpression reversed the inhibitory effects of cisplatin on NPC cell malignant phenotype in the presence of SPINK5 overexpression. In conclusion, CEBPB silencing promoted chemoresistance of NPC cells via activating SPINK5, signifying that targeting CEBPB was a new approach to enhance the chemotherapy efficacy in NPC.

Clinical significance of kallikrein 5 as a novel prognostic biomarker in gastric adenocarcinoma

Backgrounds

Gastric cancer is one of the most common cancers with unsatisfied prognosis. It is challenging to predict gastric cancer prognosis due to its highly heterogeneous nature. Kallikrein 5 (KLK5) belongs to the family of kallikreins, which plays a crucial role in serine proteolysis and exerts diverse physiological functions. The role of KLK5 in human gastric adenocarcinoma (GAC) has not been elucidated. In the present study, we aimed to examine the expression level of KLK5 and dissect whether the KLK5 expression was associated with GAC prognosis.

Patients and methods

Clinicopathological analyses were performed in a retrospective GAC patient cohort (n = 138). The expression of KLK5 was tested by quantitative RT‐PCR and immunohistochemistry staining. The prognostic role of KLK5 in GAC was assessed by univariate and multivariate analyses. The effects of KLK5 on cell proliferation, migration, and invasion were examined through cellular experiments.

Results

The data showed that KLK5 expression was elevated in GAC tissues compared with normal stomach tissues. Protein expression of KLK5 was positively correlated with tumor invasion depth and lymph node metastasis. Patients with higher KLK5 expression had poorer overall survival. KLK5 was identified to be an independent risk factor according to multivariate analysis. Using human GAC cell lines, we found that KLK5 can promote tumor cell migration and invasion.

Conclusions

Our study demonstrated that higher expression of KLK5 was significantly correlated with a poorer prognosis of GAC patients, implying the potential of KLK5 as a novel prognostic biomarker in GAC.

Kallikrein 5 Inhibition by the Lympho-Epithelial Kazal-Type Related Inhibitor Hinders Matriptase-Dependent Carcinogenesis

Head and neck squamous cell carcinoma remains challenging to treat with no improvement in survival rates over the past 50 years. Thus, there is an urgent need to discover more reliable therapeutic targets and biomarkers for HNSCC. Matriptase, a type-II transmembrane serine protease, induces malignant transformation in epithelial stem cells through proteolytic activation of pro-HGF and PAR-2, triggering PI3K-AKT-mTOR and NFKB signaling. The serine protease inhibitor lympho-epithelial Kazal-type-related inhibitor (LEKTI) inhibits the matriptase-driven proteolytic pathway, directly blocking kallikreins in epithelial differentiation. Hence, we hypothesized LEKTI could inhibit matriptase-dependent squamous cell carcinogenesis, thus implicating kallikreins in this process. Double-transgenic mice with simultaneous expression of matriptase and LEKTI under the keratin-5 promoter showed a prominent rescue of K5-Matriptase^+/0 premalignant phenotype. Notably, in DMBA-induced SCC, heterotopic co-expression of LEKTI and matriptase delayed matriptase-driven tumor incidence and progression. Co-expression of LEKTI reverted altered Kallikrein-5 expression observed in the skin of K5-Matriptase^+/0 mice, indicating that matriptase-dependent proteolytic pathway inhibition by LEKTI occurs through kallikreins. Moreover, we showed that Kallikrein-5 is necessary for PAR-2-mediated IL-8 release, YAP1-TAZ/TEAD activation, and matriptase-mediated oral squamous cell carcinoma migration. Collectively, our data identify a third signaling pathway for matriptase-dependent carcinogenesis in vivo. These findings are critical for the identification of more reliable biomarkers and effective therapeutic targets in Head and Neck cancer.